Abstract

The nonlinear dielectric response in (Na0.52K0.4425Li0.0375)(Nb0.92−xTaxSb0.08)O3ceramics with different amounts of Ta was measured using subcoercive electric fields and quantified by the Rayleigh model. The irreversible extrinsic contribution, mainly caused by the irreversible domain wall translation, was strongly dependent on the domain configuration. The irreversible extrinsic contributions remained approximately the same within the single-phase regions, either orthorhombic or tetragonal, due to the similar domain morphology. However, in the polymorphic phase transition region, the domain wall density was increased by minimized domain size, as observed by transmission electron microscopy. This resulted in constrained domain wall motion due to self-clamping and reduced the irreversible extrinsic contribution.

The authors would like to acknowledge the support of Professor Jürgen Rödel and Dr. Eva Sapper from the Technical University Darmstadt. The work was supported by Ministry of Sciences and Technology of China through National Basic Research Program of China (973 Program No. 2015CB654604), National Natural Science Foundation of China for Creative Research Groups (Grant No. 51221291), and National Natural Science Foundation of China (Grant Nos. 51272123 and 51332002).